The present invention relates to a navigation and aerial guidance system operating under the principle of altitude i.e. elevational data correlation, using a storage facility which holds terrain elevation data of a particular area in a format as actually acquired, and, also suitably processed reference data; the system uses also a sensor cooperating with a correlator that uses these reference data in order to obtain as accurate as possible information of the whereabouts of the particular aircraft.
Navigational systems of the type to which the invention pertains are for example known through German printed patent application 30 11 556 (see also U.S. Pat. Ser. No. 249,205, filed 03/30/1981). The operation of systems of this type uses particularly actually acquired and stored elevational reference data and is in fact quite suitable to obtain navigational information, whereby however the quality and accuracy of these data depend more or less, on the extensiveness of the equipment by means of which, on the one hand, correlation is determined, and on the other hand how detailed (resolution) the information as to elevational specifics is supposed to be, for both, reference data and running elevational measurements on overflight.
The navigational equipment of the publication mentioned above permits tracking along any aerial path, whereby the actually acquired elevational data during overflight are used for updating the reference data once correlation was found. The accuracy thus obtained, particularly on account of the updating is substantial, but it is an ongoing task to increase further accuracy of the equipment, without commensurate increase in complexity.